The present invention is directed to slot diffusers or air bars that control air flow from a ventilation plenum into a room and, in particular, to improvements in bridges which support air control blades within the diffusers.
Air diffusers are used in many different architectural environments for controlling the flow of air form heating and cooling ventilation systems into a room. Because of requirements associated with the geometry of a particular room and because of uneven heating or cooling requirements caused by sunlight or other heating or cooling loads in specific locations, it is often desirable to direct the air flow from the delivery plenum in a particular configuration to best suit the needs of the room.
In some instances it is best to have the air flow be a jet-type flow which comes straight out into the room. In other instances the air flow will be more diffuse and/or dampened. And in still other situations it may be desirable to direct air flow to one side or to the other side of the diffuser so that the air travels along a ceiling or wall adjacent to the diffuser.
Prior art diffusers have included various air flow controlling surfaces for distribution of the air exiting therefrom. For example, the Hungerford patent U.S. Pat. No. 5,001,967 illustrates a diffuser having air control blades that are adjustable by rotation within the diffuser and act in conjunction with body surfaces of the diffuser in an attempt to control the flow of the air from the diffuser.
Where distribution of air flow to the side is desired or where dampened air flow is desired, air flow is usually diverted in some manner within the diffuser so that it does not pass straight through the diffuser. In the present invention, a pair of air control blades work in cooperation with each other and with other surfaces of the diffuser to control air flow. The air flow control blades are positioned to be generally perpendicular to the air flow passing through the diffuser. The blades are supported by bridges within the diffuser and are preferably slidable along the bridges so that the blades can be moved relative to each other in order to control the amount of overlap of one blade over the other which in turn controls the flow of air through the diffuser. The blades are also movable with respect to the bridges and, in particular the blades can also be moved toward one side or the other of the diffuser to operably control the directional output of the air from the diffuser.
One problem encountered with movement of blades in this manner is that the blades tend to cock or turn slightly out of alignment with slots receiving the blades such that the blade either incurs sufficient drag to become very hard to move or becomes fully wedged and immobilized. It is also desirable to have a constant slight bias against the blades to hold them in position and to reduce the likelihood that the blades will rattle.
Consequently, it is desirable to provide a system for supporting the air control blades in such a manner as to prevent wedging of the blades so as to allow the blades to move smoothly and easily relative to the diffuser and each other, while also holding the blades in place and reducing rattling. In this manner a technician can properly adjust the blades during installation or to modify the position of the blades at a later time.